A 40-year-old ex-soldier called Wade Michael Page has been identified as the suspect who shot dead six in a Sikh temple in Oak Creek, Wisconsin, on Sunday.
Page was killed by armed police after the rampage, during which three others were critically injured, including a police officer.
According to his Myspace profile page, Page played in a band called End Apathy.
Alleged gunman Page was killed in a shootout with police
He wrote on his bio: "The music is a sad commentary on our sick society and the problems that prevent true progress."
ABC News reported sources as saying that the suspect was a "white supremacist" and "a skinhead".
Fox News, meanwhile, said that Page once served in the US Army and was based in Fort Bragg in North Carolina.
According to the BBC, Page had been demoted.
The Southern Poverty Law Center, a group that describes itself as being dedicated to fighting bigotry and hatred, described Page as "a frustrated neo-Nazi who had been the leader of a racist white-power band".
A motive for the attack has not emerged yet.
Photos from the scene:
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A man reacts outside the Sikh Temple of Wisconsin in Oak Creek, Wis. where a shooting took place on Sunday, Aug. 5, 2012. (credit:AP)
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Bystanders look on as SWAT officers surround the Sikh Temple of Wisconsin where at least one gunman stormed a mass and opened fire August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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Police SWAT officers surround the Sikh Temple of Wisconsin where at least one gunman stormed the mass and opened fire August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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A police officer surrounds the Sikh Temple of Wisconsin where at least one gunman stormed the mass and opened fire August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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Bystanders are directed by police officers as SWAT officers surround the Sikh Temple of Wisconsin where at least one gunman stormed a mass and opened fire August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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Police stand guard as bystanders watch at the scene of a shooting inside a Sikh temple in Oak Creek, Wis., Sunday, Aug. 5, 2012. Police and witnesses describe a chaotic situation with an unknown number of victims, suspects and possible hostages. (credit:AP)
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Bystanders stand outside the scene of a shooting inside The Sikh Temple in Oak Creek, Wis, Sunday, Aug. 5, 2012. (credit:AP)
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Police SWAT officers surround the Sikh Temple of Wisconsin where at least one gunman stormed the mass and opened fire August, 5, 2012 Oak Creek, Wisconsin. At least six people were killed when a shooter, who was shot dead by a police officer, opened fire on congregants in the Milwaukee suburb. (credit:Getty)
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Map locates Oak Creek, Wis., site of shooting at Sikh temple. (credit:AP)
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A woman reacts with others as they await word on a shooting at a Sikh temple in Oak Creek, Wis., Sunday, Aug. 5, 2012, where police and witnesses describe a chaotic situation with an unknown number of victims, suspects and possible hostages. (credit:AP)
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Bystanders sit in the shade at the scene of a shooting inside The Sikh Temple in Oak Creek, Wis, Sunday, Aug 5, 2012. Greenfield Police Chief Bradley Wentlandt says tactical officers have been through the temple where shots were fired about 10:30 a.m. Sunday. He says they found four people inside the building and three people outside. (credit:AP)
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Bystanders looks on as SWAT officers surround the Sikh Temple of Wisconsin where at least one gunman stormed a mass and opened fire August, 5, 2012 Oak Creek, Wisconsin. At least six people were killed when a shooter, who was shot dead by a police officer, opened fire on congregants in the Milwaukee suburb. (credit:Getty)
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Bystanders looks on as SWAT officers surround the Sikh Temple of Wisconsin where at least one gunman stormed a mass and opened fire August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty)
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Armed police investigate the Sikh Temple in Oak Creek, Wis. where a shooting took place on Sunday, Aug. 5, 2012. (credit:AP)
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Bystanders looks on as SWAT officers surround the Sikh Temple of Wisconsin where at least one gunman stormed a mass and opened fire August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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A bystander looks on as SWAT officers surround the Sikh Temple of Wisconsin where at least one gunman stormed a mass and opened fire August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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A woman talks on her phone outside The Sikh Temple in Oak Creek, Wis., where a shooting took place Sunday, Aug. 5, 2012. (credit:AP)
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Police personnel move outside the Sikh Temple in Oak Creek, Wis, where a shooting took place Sunday, Aug. 5, 2012. (credit:AP)
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People watch police personnel outside the Sikh Temple in Oak Creek, Wis., where a shooting took place Sunday, Aug 5, 2012. (credit:AP)
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Police personnel move outside the Sikh Temple in Oak Creek, Wis., where a shooting took place Sunday, Aug 5, 2012. (credit:AP)
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Police personnel move outside the Sikh Temple in Oak Creek, Wis., where a shooting took place Sunday, Aug 5, 2012. (credit:AP)
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A police officer talks with bystanders outside the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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Various police personnel look into a parked vehicle outside the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service August, 5, 2012 Oak Creek, Wisconsin. At least six people were killed when a shooter, who was later shot dead by a police officer, opened fire on congregants in the Milwaukee suburb. (credit:Getty Images)
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A man wipes away tears outside the Sikh Temple in Oak Creek, Wis. where a shooting took place on Sunday, Aug 5, 2012. (credit:AP)
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A tactical officer walks past the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service August, 5, 2012 Oak Creek, Wisconsin. (credit:Gett Images)
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Women walk with a red cross worker outside the Sikh Temple in Oak Creek, Wi, where a shooting took place Sunday, Aug 5, 2012. (credit:AP)
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People mill around in front of the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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An ambulance drives down Howell Ave as SWAT officers surround the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service August, 5, 2012. (credit:Getty Images)
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A tactical officer runs to position as SWAT officers surround the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service on August, 5, 2012. (credit:Getty Images)
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SWAT officers surround the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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People look on in front of the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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People wait for word on family and friends in front of the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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Police guard the front of the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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Police guard the front of the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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People mill around in front of the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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A police officer guards an area in front of the Sikh Temple of Wisconsin where at least one gunman fired upon people at a service August, 5, 2012 Oak Creek, Wisconsin. (credit:Getty Images)
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A woman uses a phone as people react outside the Sikh Temple of Wisconsin in Oak Creek, Wi, where a shooting took place Sunday, Aug 5, 2012. (credit:AP)